Polymer synthetic chemistry can now provide remarkable control over polymer microstructures, including the placement of associating functional groups. We have studied various precise polymer architectures focusing on connecting the microstructure to self-assembled morphologies and transport properties. This talk will highlight two types of polymers. First, a set of segmented ionomers containing polar units with one neutralized sulfonate groups separated by a precise number (n = 10 - 48) of methylene groups (PESn-X) were synthesized in Prof. Stefan Mecking’s group. These PESn-X ionomers exhibit exceptional long-range order and order-order transitions reminiscent of block copolymers and we have constructed phase diagrams for comparison with theoretical predictions of multiblock copolymers. The PES12-Li polymer exhibits a disordered morphology above 120 °C and we applied the RPA theory for multiblock copolymers to extract the chi parameter. With respect to ion conductivity, the most promising of the ordered structures is the double gyroid structure that exhibits higher ionic conductivity than the isotropic layered or hexagonal morphologies. Second, Prof. Justin Kennemur’s group uses ring opening polymerization to produce a linear polyethylene with a functional group on every fifth carbon. When the functional group is a phenyl sulfonate and the polymer is hydrated, we found exceptional proton conductivity that is the result of percolated nanoscale water channels. Synthetic control over polymer microstructure undeniably promotes polymer physics understanding and consequently improves property control.
